The present invention relates to swing-type actuators for disk drive assemblies and, more particularly, to a device for locating and securing terminal pins in a mold relative to a coil prior to an injection molding step in the manufacture of swing-type actuators.
Numerous swing-type actuators are known in the prior art. Typically, such actuators include an arm joined to a coil. A read/write head is mounted to the arm for reading data from and writing data to a computer disk. The arm is typically mounted about a shaft around which it rotates. The coil is disposed in a magnetic field. Lead wires from the coil are joined to terminal pins. When current is applied to the coil via the terminal pins, a magnetic field is set up about the coil. This causes the coil to move in the field in which it is already located. As the coil moves, the arm attached thereto also moves, thereby positioning the read/write head on the disk.
In the above described actuator, the coil may be attached to the arm of the actuator by means of a molded thermoplastic member. To do so, the coil, terminal pins and arm are placed in a mold. The mold is then injected with a thermoplastic material that surrounds at least part of the coil, terminal pins and arm. After the thermoplastic material sets, the completed actuator is removed from the mold.
Although the above described method of manufacturing an actuator is acceptable, it sometimes results in improper placement of the terminal pins relative to the coil. This may result from movement of the coil, terminal pins or both during the molding process. Additionally, the lead wires from the coil may "float" in the thermoplastic material during molding. If the wires come in contact during molding and remain that way after the thermoplastic material sets, the resulting short makes the actuator useless. Additionally, the lead wires may be stressed during the molding process by the flow of the thermoplastic material. This can result in broken lead wires.
It is an object of the present invention to provide a device for locating and securing terminal pins in a mold relative to a coil prior to an injection molding step in a manufacturing process.
Another object of the present invention is to provide means for attaching a coil to a swing-type actuator that prevents the lead wires of the coil from developing a short during manufacture.
Yet another object of the present invention is to provide means for reducing stress on the lead wires of a swing-type actuator coil during manufacture.
These and other objects of the present invention are attained by the provision of a device including a body formed to be disposed adjacent a surface of the coil, a plurality of terminal pin sleeves and a bridge member joining the body and the sleeves. In one embodiment of the invention, the body is disposed adjacent an inner circumferential surface of the coil, and the outer circumference of the body is smaller than the inner circumference of the coil such that the body may be press-fit within the coil. At least a portion of the body has a thickness less than the thickness of the coil.
According to another embodiment of the invention, the device includes means for locating the device in a mold. The means for locating the device in a mold may include at least one projection on the body.
The bridge member may also include means for reducing the stress on the coil lead wires during a molding process. The means may include a raised wire guide on the bridge member and a slot in the bridge member.
In one embodiment of the invention, the body extends completely around the interior circumference of the coil.
In yet another embodiment of the present invention, the body is a slotted coil retention member that receives a portion of the coil. The bridge member is thinner than the body and is disposed in substantially the same plane as the coil.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.